Are There Levels of Consciousness? Tim Bayne, Jakob Hohwy, Adrian M. Owen  Trends in Cognitive Sciences  Volume 20, Issue 6, Pages 405-413 (June 2016) DOI: 10.1016/j.tics.2016.03.009 Copyright © 2016 The Authors Terms and Conditions

Figure 1 Conceptual Sketch of Multidimensional Global States of Consciousness. The radar charts depict regions in a multidimensional space that reflect different states of consciousness. Numbers at the radii are placeholders for the dimensions of consciousness, they may correspond to a family of content-related (e.g., content gating and content range) and functional dimensions (e.g., relating to attentional control, memory consolidation, verbal report, reasoning, action selection, etc.). The figures here do not portray empirically grounded results but are merely illustrative of possible dimensional analyses of states of consciousness. For further discussion, see main text. (A) Global states may not possess an absolute ordering if they differ in different dimensions; for example, rapid eye movement (REM) dreaming and mild sedation could be high and low in roughly opposite dimensions. (B) Multidimensionality raises the possibility of considerable variability within categories that are currently assumed to involve a single global state of consciousness; for example, the global conscious states of certain MCS patients might resemble those of certain VS or EMCS patients more closely than they do other MCS patients. (C) Interactions between dimensions may lead to non-linear transitions between states, raising the possibility of regions that cannot be occupied; for example, for the difference between VS and MCS, it could be that being low in one dimension forces a low score in another dimension, ruling out certain intermediate states. (D) The traditional two-dimensional representation of consciousness (e.g., [1,41]), which obscures scenarios such as those represented by (A–C) and discussed in the main text. Reproduced from [1]. Trends in Cognitive Sciences 2016 20, 405-413DOI: (10.1016/j.tics.2016.03.009) Copyright © 2016 The Authors Terms and Conditions